Microplastics (less than 5 mm) are a recognized threat to aquatic food webs because they are ingested at multiple trophic levels and may bioaccumulate. In urban coastal environments, high densities of microplastics may disrupt nutritional intake. However, behavioural dynamics and consequences of microparticle ingestion are still poorly understood. As filter or suspension feeders, benthic marine invertebrates are vulnerable to microplastic ingestion. We explored microplastic ingestion by the temperate coral Astrangia poculata . We detected an average of over 100 microplastic particles per polyp in wild-captured colonies from Rhode Island. In the laboratory, corals were fed microbeads to characterize ingestion preference and retention of microplastics and consequences on feeding behaviour. Corals were fed biofilmed microplastics to test whether plastics serve as vectors for microbes. Ingested microplastics were apparent within the mesenterial tissues of the gastrovascular cavity. Corals preferred microplastic beads and declined subsequent offerings of brine shrimp eggs of the same diameter, suggesting that microplastic ingestion can inhibit food intake. The corals co-ingested Escherichia coli cells with microbeads. These findings detail specific mechanisms by which microplastics threaten corals, but also hint that the coral A. poculata , which has a large coastal range, may serve as a useful bioindicator and monitoring tool for microplastic pollution.

Ocean plastic pollution is a global problem that causes ecosystem degradation. Crucial knowledge gaps exist concerning patterns in microfiber abundance across regions and ecosystems, as well as the role of these pollutants within the environment. Here, we quantified the abundance of microfibers in coral samples collected from the Belize Mesoamerican Barrier Reef System (MBRS) using a polarized light microscope and identified a subsample of these to the polymer level using an Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy microscope. Microfibers were found in all coral samples with rayon being identified as the most common microfiber, comprising 85% of quantified pollutants. We found a greater average abundance of microfibers in coral samples from the Sapodilla Cayes (296 ± SE 89) than in samples from the Drowned Cayes (75 ± SE 14), indicating spatial variation in microfiber abundance within coral tissue along the MBRS. These results demonstrate that corals on the Belize MBRS interact with microfibers and that microfiber abundance on reefs varies spatially due to point sources of pollution and local oceanography. As rayon from clothing typically enters the ocean through wastewater effluent, alterations to waste water infrastructure may prove useful in decreasing rayon pollution in coastal waters.

In March 2020, COVID-19 disrupted global society. Impacts as a result of COVID-19 were seen in all industries, including higher education research, which was paused in order to accommodate newly imposed restrictions. Social science research, specifically stakeholder engagement research, was one area that was potentially impacted given its need for person-to-person interaction. Here, we describe how we successfully adjusted our stakeholder engagement methodology to accommodate for socially distant requirements. Initially, we planned to host in-person workshops to assess stakeholder perceptions of microplastics impacts on oysters in Boston Harbor and coastal Massachusetts using the deliberative multicriteria evaluation (DMCE) methodology. To transfer these workshops online, we used familiar, open-access platforms, Zoom and GoogleDrive, to enable dialogue among participants and evaluate preferences. While modifications to length (5 to 3 h) and order (participants were asked to watch expert videos before their participation date) of the workshop were necessary, most other elements of the methodology remained the same for the online format. The main element that was lacking was the in-person interactions. However, with video conferencing tools available, this element was not completely lost.

Laboratory experiments were conducted with Calanus finmarchicus copepodites IV–V to examine the effects of food concentration, food type, and life stage on chromophoric dissolved organic matter (CDOM) release from copepods. Changes in CDOM absorption and fluorescence were monitored by incubating copepods in rotating bottles for 24 h in the dark with controlled diets. Copepods were fed a range of food concentrations from 800 to 15 000 cells l−1 of either Thalassiosira weissflogii and Skeletonema costatum or Prorocentrum minimum in stationary and exponential growth phases. Results from these studies indicate that diet does have an effect on the amount and type of CDOM released by C. finmarchicus. A diet of either diatoms or dinoflagellates in exponential growth will result in a release of humic-like material, while feeding on senescent cells leads to a net input of protein-like material. Only at very high senescent cell concentrations (>5000 cells l−1) can humic-like material accumulate. This could lead to seasonal cycles in the amount and type of CDOM released by copepods, such that humic-like material will be released in the spring and at the height of phytoplankton blooms, while protein-like material will be added to the water as the bloom dies. The humic-like material found in these studies is blue-shifted compared to the standard humic material (Peaks A, M, and C) measured in seawater. The role of this humic-like material in the environment is currently unknown, but it could be important in absorbing UV radiation.

The effects of phytoplankton community composition on faecal pellet carbon concentrations from a mixed community of large (>500 μm) copepods were examined in studies in two areas: Balsfjord, Norway, and the Pacific sector of the Antarctic Polar Front. The Balsfjord study was conducted during the spring bloom of 1994. Faecal pellet production rates, dry weights and total amino acid carbon concentrations were positively correlated with chlorophyll concentrations. However, faecal pellet carbon concentrations were not correlated to chlorophyll levels but rather appeared related to the phytoplankton community composition. Lower faecal pellet carbon concentrations were consistently found when diatoms constituted >50% of the available plankton. Similar results were found in the Antarctic Polar Front study, which was conducted during the austral spring and summer of 1997–1998. Over spring and summer, faecal pellet carbon concentrations were negatively correlated with particulate biogenic silica concentrations. Results from both of these field studies suggest that, on a community level, the diet of copepods affects the carbon concentration of the pellets and thus the potential flux of carbon via faecal pellets.